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ILLINOIS STATE LIBRARY


Historical Topographic Quadrangles

The eight inventories below represent the complete collection of superseded U.S. Geological Survey (USGS) topographic quadrangles for the six states bordering Illinois held by the Illinois State Library.

The first six lists consist of the superseded 1:24,000 (7 1/2 minute) scale quads for each of the six states: Indiana, Iowa, Kentucky, Michigan, Missouri and Wisconsin. The latest quads are not listed. The last two lists inventory the 1:62,500 (15 minute) and the 1:125,000 scale quads respectively for the same six states. Any quad showing Illinois territory is listed on the Illinois Large-Scale Topographic Quadrangles.

Inventories

Column Explanations for the 7 1/2 Lists

QuadName: The lists are generally alphabetical by the name of the quad as printed on the map. The name was taken exactly from the printed quad, which means some quads have "Mount" abbreviated and some do not, quads which have two states listed sometimes changed the order of the two states between editions, and one word names have become two or vice versa. The state name has been omitted when it is a single state only but given when it is two or more. Those quads with "IL" in the name on these lists show no Illinois territory. Quads showing territory in two states of the six are listed in the inventory of the state named first on the quad.

SortDate (and other date columns): These inventories were created using Microsoft Access. Since separate columns exist for survey, printing, edition, revision, reprint, and photoinspection dates, the creation of a "sortdate" column was necessary to induce the computer to produce a list in the proper order, as it could not sort through all these columns to pick out the latest date from any column. This column keeps the different editions in chronological order and is a condensed version of all the various kinds of revision that a topo quad may have. "P" in the edition column indicates a provisional edition. "PR" in the revision column means photorevised.

QuadNumber: The USGS code for the 7 1/2 quads, based on 1-degree blocks of latitude and longitude plus an alphanumeric for each quad, is given. ISL does not use these quad numbers for filing or retrieving, but the map index does.

Column explanations for the 1:62,500 and 1:125,000 lists

State: Each of these lists contain all six states, organized alphabetically first by state.

QuadName: Secondary organization is alphabetically by the name of the quad.

Date: The several date columns in the 7 1/2 lists have been reduced to one date column, in chronological order with latest first.

Index: The index column merely indicates whether or not the quad has been marked off on the oldest index map the State Library owns for that state. These quads do not show on the current topo indexes, nor was the whole state in each case necessarily mapped on the 1:62,500 scale, so marking the available graphic index helped estimate the percentage of the potential collection that the State Library holds and will help users locate the needed quad as well.

In addition: The print version also lists the few 1:62,500 and 1:125,000 "special" quads that are cataloged, classed, and represented in the State Library's catalog.

Availability: The State Library can make color to-scale photocopies upon request for a fee, but does not sell the originals. For more information, or to obtain a print version of the inventories, please call 217-782-7596 or e-mail islinfo@ilsos.net.